1. Technical Field
The present invention relates to a voltage output circuit, an electronic apparatus, a moving object, a manufacturing method for the voltage output circuit, and a manufacturing method for the electronic apparatus.
2. Related Art
A real-time clock (RTC) circuit and the like are circuits including a clocking function and are incorporated in a variety of electronic apparatuses such as a personal computer. In general, the RTC circuit and the like are required to continue clocking even when main power supplies of the electronic apparatuses are disconnected or when main power is not temporarily supplied because of momentary power interruption. Therefore, circuits for detecting that the main power supplies are interrupted and switching power supplies of the RTC circuit and the like to backup power supplies are provided. For example, JP-A-2009-131129 (Patent Literature 1) proposes a power supply switching circuit that, when a voltage of a main power supply is equal to or higher than a switching voltage, charges a backup power supply with the main power supply and supplies electric power to an RTC circuit and, when the voltage of the main power supply drops to a voltage lower than the switching voltage, disconnects the main power supply and the RTC circuit and supplies electric power from the backup power supply to the RTC circuit.
However, in the power supply switching circuit described in Patent Literature 1, for example, in assembly of an electronic apparatus, when the main power supply is incorporated after the backup power supply is incorporated, power supply from the backup power supply to the RTC circuit is unnecessary before the main power supply is started after the backup power supply is incorporated. However electric power is supplied from the backup power supply to the RTC circuit. Therefore, electric power accumulated in the backup power supply is consumed. In particular, when the backup power supply is a primary battery, the backup power supply cannot be charged after the assembly of the electronic apparatus. Therefore, this problem is serious.